Effects of lubricant and lubrication parameters on friction during hot steel forging

The aim of the present work is to improved comprehension of wear phenomenon during hot steel forging with sprayed lubricants. The study reported in this paper uses a specific friction test, called the Warm Hot Upsetting Sliding Test (WHUST), which reproduces hot forging contact conditions. Wear markers –such as friction force/normal load ratio or sliding distance before the first scratch– are proposed to characterize the contactor wear at microscopic and macroscopic scales. Friction tests are performed on 1100°C heated specimens to characterize the influence of graphite based lubricant film thickness and particle sizes on friction and wear in the flash zone of a nitrided steel die.